# US 2014/0155723 A1 · Multi-channel ecg measurement > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2014/0155723 A1 - Document ID: US20140155723A1 - Status: Published application - Kind: A1 - Application number: 13/693,099 - Filed: 2012-12-04 - Published: 2014-06-05 - Earliest claimed: 2012-12-04 - Assignees: Biosense Webster (Israel) Ltd. - Inventors: Michael Levin; Meir Bar-Tal - Web page: https://patentgrep.com/patent/US20140155723A1 ## CPC - A61B 5/7217: {of noise originating from a therapeutic or surgical apparatus, e.g. from a pacemaker} - A61B 5/282: Holders for multiple electrodes (for introduction into the body A61B5/287) - A61B 5/296: for electromyography [EMG] - A61B 5/305: Common mode rejection - A61B 5/308: for electrocardiography [ECG] - A61B 5/327: Generation of artificial ECG signals based on measured signals, e.g. to compensate for missing leads - A61B 5/347: Detecting the frequency distribution of signals - A61B 5/6824: {Arm or wrist} - A61B 5/6828: {Leg} - A61B 5/7203: {for noise prevention, reduction or removal} - A61B 5/7228: {Signal modulation applied to the input signal sent to patient or subject; Demodulation to recover the physiological signal} - A61B 2560/0223: of calibration, e.g. protocols for calibrating sensors - A61B 2562/0209: Special features of electrodes classified in A61B5/24, A61B5/25, A61B5/283, A61B5/291, A61B5/296, A61B5/053 - A61B: DIAGNOSIS; SURGERY; IDENTIFICATION (usefulness limited to only animals A61D) ## Abstract A method for acquiring electrical signals from a living subject, including injecting, via an injection electrode attached to the subject, a known calibration signal to the subject and measuring respective levels of output signals generated at input electrodes attached to the subject in response to the calibration signal. The method further includes deriving respective weighting factors for the input electrodes in response to the respective levels, and applying the respective weighting factors to physiological signals acquired by the input electrodes, so as to generate respective corrected physiological signals. ## Claims ### Claim 1 A method for acquiring electrical signals from a living subject, comprising: injecting, via an injection electrode attached to the subject, a known calibration signal to the subject; measuring respective levels of output signals generated at input electrodes attached to the subject in response to the calibration signal; deriving respective weighting factors for the input electrodes in response to the respective levels; and applying the respective weighting factors to physiological signals acquired by the input electrodes, so as to generate respective corrected physiological signals. ### Claim 2 (depends on 1) The method according to claim 1, wherein the physiological signals comprise signals generated from electrophysiological processes occurring in the subject. ### Claim 3 (depends on 1) The method according to claim 1, wherein the physiological signals comprise signals generated externally to the subject, and which are coupled into the subject. ### Claim 4 (depends on 1) The method according to claim 1, wherein the known calibration signal has a preset frequency, and wherein measuring respective levels of the output signals comprises measuring the respective levels at the preset frequency. ### Claim 5 (depends on 1) The method according to claim 1, wherein the respective levels comprise respective amplitude levels generated at the input electrodes, and wherein the respective weighting factors are derived in response to inverse values of the respective amplitude levels. ### Claim 6 (depends on 1) The method according to claim 1, wherein the respective levels comprise respective phase levels generated at the input electrodes, and wherein the respective weighting factors are derived in response to negative values of the respective phase levels. ### Claim 7 (depends on 1) The method according to claim 1, wherein the physiological signals comprise bipolar signals, and wherein the corrected physiological signals comprise corrected bipolar signals. ### Claim 8 (depends on 1) The method according to claim 1, wherein the physiological signals comprise unipolar signals, and wherein the corrected physiological signals comprise corrected unipolar signals. ### Claim 9 (depends on 1) The method according to claim 1, wherein the input electrodes comprise three electrodes respectively attached to a right arm (RA), a left arm (LA), and a left leg (LL) of the subject, and wherein applying the respective weighting factors to the three physiological signals acquired by the three electrodes comprises averaging the three corrected physiological signals generated from the three electrodes to provide a reference signal. ### Claim 10 Apparatus for acquiring electrical signals from a living subject, comprising: an injection electrode attached to the subject; input electrodes attached to the subject; and a processor, which is configured to: inject a known calibration signal to the subject via the injection electrode, measure respective levels of output signals generated at the input electrodes in response to the calibration signal, derive respective weighting factors for the input electrodes in response to the respective levels, and apply the respective weighting factors to physiological signals acquired by the input electrodes, so as to generate respective corrected physiological signals. ### Claim 11 (depends on 10) The apparatus according to claim 10, wherein the physiological signals comprise signals generated from electrophysiological processes occurring in the subject. ### Claim 12 (depends on 10) The apparatus according to claim 10, wherein the physiological signals comprise signals generated externally to the subject, and which are coupled into the subject. ### Claim 13 (depends on 10) The apparatus according to claim 10, wherein the known calibration signal has a preset frequency, and wherein measuring respective levels of the output signals comprises measuring the respective levels at the preset frequency. ### Claim 14 (depends on 10) The apparatus according to claim 10, wherein the respective levels comprise respective amplitude levels generated at the input electrodes, and wherein the respective weighting factors are derived in response to inverse values of the respective amplitude levels. ### Claim 15 (depends on 10) The apparatus according to claim 10, wherein the respective levels comprise respective phase levels generated at the input electrodes, and wherein the respective weighting factors are derived in response to negative values of the respective phase levels. ### Claim 16 (depends on 10) The apparatus according to claim 10, wherein the physiological signals comprise bipolar signals, and wherein the corrected physiological signals comprise corrected bipolar signals. ### Claim 17 (depends on 10) The apparatus according to claim 10, wherein the physiological signals comprise unipolar signals, and wherein the corrected physiological signals comprise corrected unipolar signals. ### Claim 18 (depends on 10) The apparatus according to claim 10, wherein the input electrodes comprise three electrodes respectively attached to a right arm (RA), a left arm (LA), and a left leg (LL) of the subject, and wherein applying the respective weighting factors to the three physiological signals acquired by the three electrodes comprises averaging the three corrected physiological signals generated from the three electrodes to provide a reference signal.